"My English teacher was the sitcom Friends," he explained. "Back in the days, when I was like 15, 14, it was quite like a syndrome for all the Korean parents to make their kids watch Friends. I thought I was kind of like a victim at that time, but right now, I'm the lucky one, thanks to my mother. She bought me all 10 DVDs — all the seasons. So firstly, I watched them with the Korean subtitles, and then next time, I watched with the English subtitles, and then I just removed it." That sounds way more fun than learning a language in a classroom.

The band also gave a show-stopping performance of Mic Drop. The audience went wild as they danced in matching black jackets and skinny jeans.

"When you got to LA, it was like the Beatles were here," Ellen told them. And there really were more screams than we've ever heard coming from Ellen's audience.